944
C A N A D I A N J O U R N A L OF A N A E S T H E S I A
REFERENCES
1 Harris CE, Murray AM, Anderson JM, Grounds RM, Morgan M. Effects of thiopentone, etomidate and
propofol on the hemodynamic response to tracheal intubation. Anaesthesia 1988; 43: 32-6. 2 Dundee JW, Robinson FP, McCollum JSC, Patterson CC. Sensitivity to propofol in the elderly. Anaesthesia
1986; 41: 482-5. 3 Doenicke A, Lorenz W, Stanworth D, Duha T, Geln JB. Effects of propofol on histamine release, immuno-
globulin levels and activation of complement in healthy volunteers. Postgrad Med J 1985; 61: 15-20.
An unusual reaction to
precurarization To the Editor: We recently witnessed an unusual reaction to "precurarization". An ASA I, 40-yr-old Caucasian female presented for varicose vein surgery. Her medical history included tonsillectomy, migraine headaches and allergies to penicillin and tape. No premedication was ordered. Midazolam 1 mg was administered iv on arrival outside the operating room. In the operating room, standard monitors and an automatic BP cuff were placed. Her BP was 110/72 mmHg and HR 118" min -l. Oxygen was applied by mask and d-tubocurarine 3 mg was administered iv. At this time the patient complained of "tingling and pins and needles" on the scalp and raised her hands to hold her head. Erythematous wheals were evident on the arm proximal to the iv site. Vital signs were unchanged and the patient was reassured. Within seconds she became very distressed, grabbed her head and complained of pain like "pins and needles" in her head. Her entire skin became bright red and warm. The BP was 128/83 mmHg and HR 115 .min -1. The patient was severely distressed and remained conscious with no obvious neurological deficits. Because of the patient's discomfort but haemodynamic stability, she was anaesthetized with thiopentone and tracheal intubation was facilitated with succinylcholine. Anaesthesia was maintained with N20:O2 (70:30) and isoflurane. Blood pressure, heart rate and oxygen saturation remained stable throughout the period of the reaction and anaesthesia. Within five minutes of induction, the cutaneous vasodilatation had resolved completely. There was no evidence of bronchospasm, oedema or urticaria. Surgery proceeded uneventfully and recovery from anaesthesia was normal. In the recovery room she was pain free, had no neurological deficit, headache or rash, but complained of being cold.
Unfortunately the patient was not followed up with allergy testing, as recommended by Watkins. ~ We can offer no completely satisfactory explanation for this reaction but suggest that the history of migraine may have played a role. Acute cerebral vasodilatation due to histamine release may possibly be a basis for certain migraine headaches and this might suggest a mechanism for the reaction observed following iv d-tubocurarine. 2,3 In our patient, there were signs of histamine release such as cutaneous erythema but no hypotension. No similar case could be found in the literature. Mark Friedlander MBCHa FRCPC John Brebner Mo PnD FRCPC Department of Anaesthesia The Toronto Hospital and University of Toronto, Toronto REFERENCES
1 Watkins J. Investigation of allergic and hypersensitivi-
ty reactions to anaesthetic agents. Br J Anaesth 1987; 59: 104-11. 2 Vesely R, Hoffinan WE, Gil KSL, Albrecht RF, Miletich DJ. The cerebrovascular effects of curare and hista-
mine in the rat. Anesthesiology 1987; 66: 519-23. 3 Saxena PR. Agonists and antagonists of vascular receptors. In: M. Critchley et al. (Eds.). Advances in
Neurology, Vol 33, New York: Raven Press, 1982.
The TURP syndrome To the Editor: We read with interest Dr. Jensens's article on TURP syndrome. 1 Her guidelines regarding "prevention of TURP syndrome" contain some disputed areas. (1) She advocated restricting the duration of resection to one hour although Melchoir et al., after an analysis of 2223 consecutive TURP operations, concluded that absorption is time-related only in resections which exceeded 150 min. 2 (2) With regard to limiting the hydrostatic pressure of the irrigating fluid to 70 cm of water, we wish to point out that there are two pressures in action in the operating field: the dynamic pressure of the jet and the static pressure exerted by the contents of the urinary bladder and the weight of the tissues resting on the bladder (intestines, abdominal wall etc.). Most of the driving head of pressure is lost as a result of friction and lateral losses against the tubing and the valve of the resectoscope and what is left is the final dynamic pressure in the jet. Hultrn, using an engineering model of the human bladder,
CORRESPONDENCE
measured the dynamic pressure of the jet stream with different resectoscopes, pressure heads and valve positions, obtained dynamic pressure readings of negligible magnitude (less than 1 cm of water). This was confirmed in vivo. 3
Intravenous absorption occurs if the static pressure exceeds the pressure in the opened veins of the prostatic fossa. The critical static pressure at which fluid is absorbed varies with the position of the patient. In the Trendelenburg (20 ~ position it is 0.25 kPa increasing to 1.25 kPa in the horizontal and 1.75 kPa in the head up position (200). 3 The height of the reservoir bag thus becomes irrelevant as long as one is within the static pressure limits. Extravascular absorption may occur at even lower bladder pressures. 4 (3) Monitoring serum sodium concentration to detect irrigant absorption is invasive and does not give real time absorption values of irrigant fluid. Hult6n et al. described a simple, non-invasive, sensitive, repeatable method 5 which involves tagging irrigating fluids with 1% ethanol and monitoring the expired breath ethanol concentrations using a hand-held breathalyser type of device. The technique has been used regularly in patients undergoing TURP under spinal, epidural and general anaesthesia. 5'6 With this method absorption of as little as 150 ml. 10 min-t can be instantly detected. (4) Finally, Dr. Jensen advocated spinal anaesthesia to enable early detection of cerebral symptoms during TURP. Waiting for the onset of cerebral symptoms to diagnose and treat TURP syndrome is like shutting the barn door after the horse has bolted. The TURP syndrome can be prevented by careful monitoring of the absorption events as they occur and by taking prompt steps to minimize absorption such as reducing the static pressure in the bladder to below intravascular pressure and securing haemostasis. Dr. V. Jaydev Sarma DA FFARCSI Dr. Jail O Hult6n MDPhD Departments of Anaesthesia and Urology Piteh General Hospital 941 28 PiteL Sweden REFERENCES
1 Jensen V. The TURP Syndrome. Can J Anaesth 1991;
38: 90-7. 2 Melchoir J, Valk WL, Foret JD, Mebust WK. Transureth-
ral prostatectomy: computerised analysis of 2,223 consecutive cases. J Urol 1974; 112: 634-42. 3 Hult~n JO. Prevention of irrigating fluid absorption during transurethral resection of the prostate. Doctoral thesis. Link6ping University Medical Dissertations No. 176. Link6ping University, Link6ping, Sweden, 1984.
945
4 Hultdn JO, Sundstr~m G. Extravascular absorption of
irrigating fluid during TURP. The role of transmural bladder pressure as the driving pressure gradient. Br J Urol 1990; 65: 39-42. 5 Hultdn JO, Jorfeldt LS, Wictorsson YM. Monitoring fluid absorption during TURP by marking the irrigation solution with ethanol. Scand J Uro! Nephro11986; 20: 245-51. 6 Hultdn JO, Sarma VJ, Hjertberg H, Palmquist B. Monitoring of irrigating fluid absorption during transurethral prostatectomy. A study in anaesthetised patients using a 1% ethanol tagged solution. Anaesthesia 1991: In press.
REPLY My recommendations for prevention of the TURP syndrome were intended only as general guidelines. I am happy that further discussion of this topic has been stimulated. (1) A recent series of 3,885 patients undergoing transurethral prostatectomy was reported by Mebust. He concluded that the TURP syndrome occurred in two percent of patients when the resection time was more than 90 min but in only O.7% when the resection time was less than 90 min. 1A recent review suggested that the resection time be limited to 60 min. 2 The TURP syndrome has occurred as early as after only 15 min of resection time. 3 (2) It has been suggested that the maximum allowable pressure of the irrigating fluid should be 6.9 kPa (70 cm H20), to minimize intravascular absorption. 2 lntravascular absorption occurs when the pressure in the prostatic fossa exceeds the pressure in the pelvic veins, concomitantly with an opening in the pelvic veins. Madsen concluded that absorption was lower when the irrigating fluid was maintained at 5.9 kPa (60 cm 1120) over the table than when the fluid height was maintained at 6.9 kPa (70 cm H20) and 8.8 laPa (90 cm H20. 4 Hahn determined that the intravesicular pressure could vary greatly in different patients even though the irrigating bag was maintained at the same height above the prostatic fossa. 5 He suggested that other factors such as the operating technique of the surgeon and the elastic properties of the bladder were more dominant factors in determining the intravesical pressure than the height of the irrigating bag: Hultdn concluded that the dynamic pressure of the irrigating jet is smaller than the static pressure within the bladder. 6 However, the dynamic pressure is important when the flow rate through the instrument is high and also when flow declines .6 (3) Tagging the irrigating fluid with ethanol and monitoring the expired breath ethanol concentration has been described as a noninvasive technique to detect absorption instantly. 7The rise in expired ethanol occurs immediately after intravascular absorption. 7 Sampling the expired ethanol is an intermittent technique, therefore absorption might be missed if sampling is not performed simultaneously with the absorption. The technique will follow intravascular absorption but does not detect extravascular absorption as readily.S Patients with an elevated serum creatinine concentration have a higher expired ethanol concentration than those with normal renal function, s The irrigating fluM containing 1.5% glycine and 2% ethanol in water has a high osmolality of 650 mosmol, kg -1 and the solution o f l . 5 % glycine and 1% ethanol is still hyperosmolar, s
C A N A D I A N J O U R N A L OF A N A E S T H E S I A
REFERENCES
1 Harris CE, Murray AM, Anderson JM, Grounds RM, Morgan M. Effects of thiopentone, etomidate and
propofol on the hemodynamic response to tracheal intubation. Anaesthesia 1988; 43: 32-6. 2 Dundee JW, Robinson FP, McCollum JSC, Patterson CC. Sensitivity to propofol in the elderly. Anaesthesia
1986; 41: 482-5. 3 Doenicke A, Lorenz W, Stanworth D, Duha T, Geln JB. Effects of propofol on histamine release, immuno-
globulin levels and activation of complement in healthy volunteers. Postgrad Med J 1985; 61: 15-20.
An unusual reaction to
precurarization To the Editor: We recently witnessed an unusual reaction to "precurarization". An ASA I, 40-yr-old Caucasian female presented for varicose vein surgery. Her medical history included tonsillectomy, migraine headaches and allergies to penicillin and tape. No premedication was ordered. Midazolam 1 mg was administered iv on arrival outside the operating room. In the operating room, standard monitors and an automatic BP cuff were placed. Her BP was 110/72 mmHg and HR 118" min -l. Oxygen was applied by mask and d-tubocurarine 3 mg was administered iv. At this time the patient complained of "tingling and pins and needles" on the scalp and raised her hands to hold her head. Erythematous wheals were evident on the arm proximal to the iv site. Vital signs were unchanged and the patient was reassured. Within seconds she became very distressed, grabbed her head and complained of pain like "pins and needles" in her head. Her entire skin became bright red and warm. The BP was 128/83 mmHg and HR 115 .min -1. The patient was severely distressed and remained conscious with no obvious neurological deficits. Because of the patient's discomfort but haemodynamic stability, she was anaesthetized with thiopentone and tracheal intubation was facilitated with succinylcholine. Anaesthesia was maintained with N20:O2 (70:30) and isoflurane. Blood pressure, heart rate and oxygen saturation remained stable throughout the period of the reaction and anaesthesia. Within five minutes of induction, the cutaneous vasodilatation had resolved completely. There was no evidence of bronchospasm, oedema or urticaria. Surgery proceeded uneventfully and recovery from anaesthesia was normal. In the recovery room she was pain free, had no neurological deficit, headache or rash, but complained of being cold.
Unfortunately the patient was not followed up with allergy testing, as recommended by Watkins. ~ We can offer no completely satisfactory explanation for this reaction but suggest that the history of migraine may have played a role. Acute cerebral vasodilatation due to histamine release may possibly be a basis for certain migraine headaches and this might suggest a mechanism for the reaction observed following iv d-tubocurarine. 2,3 In our patient, there were signs of histamine release such as cutaneous erythema but no hypotension. No similar case could be found in the literature. Mark Friedlander MBCHa FRCPC John Brebner Mo PnD FRCPC Department of Anaesthesia The Toronto Hospital and University of Toronto, Toronto REFERENCES
1 Watkins J. Investigation of allergic and hypersensitivi-
ty reactions to anaesthetic agents. Br J Anaesth 1987; 59: 104-11. 2 Vesely R, Hoffinan WE, Gil KSL, Albrecht RF, Miletich DJ. The cerebrovascular effects of curare and hista-
mine in the rat. Anesthesiology 1987; 66: 519-23. 3 Saxena PR. Agonists and antagonists of vascular receptors. In: M. Critchley et al. (Eds.). Advances in
Neurology, Vol 33, New York: Raven Press, 1982.
The TURP syndrome To the Editor: We read with interest Dr. Jensens's article on TURP syndrome. 1 Her guidelines regarding "prevention of TURP syndrome" contain some disputed areas. (1) She advocated restricting the duration of resection to one hour although Melchoir et al., after an analysis of 2223 consecutive TURP operations, concluded that absorption is time-related only in resections which exceeded 150 min. 2 (2) With regard to limiting the hydrostatic pressure of the irrigating fluid to 70 cm of water, we wish to point out that there are two pressures in action in the operating field: the dynamic pressure of the jet and the static pressure exerted by the contents of the urinary bladder and the weight of the tissues resting on the bladder (intestines, abdominal wall etc.). Most of the driving head of pressure is lost as a result of friction and lateral losses against the tubing and the valve of the resectoscope and what is left is the final dynamic pressure in the jet. Hultrn, using an engineering model of the human bladder,
CORRESPONDENCE
measured the dynamic pressure of the jet stream with different resectoscopes, pressure heads and valve positions, obtained dynamic pressure readings of negligible magnitude (less than 1 cm of water). This was confirmed in vivo. 3
Intravenous absorption occurs if the static pressure exceeds the pressure in the opened veins of the prostatic fossa. The critical static pressure at which fluid is absorbed varies with the position of the patient. In the Trendelenburg (20 ~ position it is 0.25 kPa increasing to 1.25 kPa in the horizontal and 1.75 kPa in the head up position (200). 3 The height of the reservoir bag thus becomes irrelevant as long as one is within the static pressure limits. Extravascular absorption may occur at even lower bladder pressures. 4 (3) Monitoring serum sodium concentration to detect irrigant absorption is invasive and does not give real time absorption values of irrigant fluid. Hult6n et al. described a simple, non-invasive, sensitive, repeatable method 5 which involves tagging irrigating fluids with 1% ethanol and monitoring the expired breath ethanol concentrations using a hand-held breathalyser type of device. The technique has been used regularly in patients undergoing TURP under spinal, epidural and general anaesthesia. 5'6 With this method absorption of as little as 150 ml. 10 min-t can be instantly detected. (4) Finally, Dr. Jensen advocated spinal anaesthesia to enable early detection of cerebral symptoms during TURP. Waiting for the onset of cerebral symptoms to diagnose and treat TURP syndrome is like shutting the barn door after the horse has bolted. The TURP syndrome can be prevented by careful monitoring of the absorption events as they occur and by taking prompt steps to minimize absorption such as reducing the static pressure in the bladder to below intravascular pressure and securing haemostasis. Dr. V. Jaydev Sarma DA FFARCSI Dr. Jail O Hult6n MDPhD Departments of Anaesthesia and Urology Piteh General Hospital 941 28 PiteL Sweden REFERENCES
1 Jensen V. The TURP Syndrome. Can J Anaesth 1991;
38: 90-7. 2 Melchoir J, Valk WL, Foret JD, Mebust WK. Transureth-
ral prostatectomy: computerised analysis of 2,223 consecutive cases. J Urol 1974; 112: 634-42. 3 Hult~n JO. Prevention of irrigating fluid absorption during transurethral resection of the prostate. Doctoral thesis. Link6ping University Medical Dissertations No. 176. Link6ping University, Link6ping, Sweden, 1984.
945
4 Hultdn JO, Sundstr~m G. Extravascular absorption of
irrigating fluid during TURP. The role of transmural bladder pressure as the driving pressure gradient. Br J Urol 1990; 65: 39-42. 5 Hultdn JO, Jorfeldt LS, Wictorsson YM. Monitoring fluid absorption during TURP by marking the irrigation solution with ethanol. Scand J Uro! Nephro11986; 20: 245-51. 6 Hultdn JO, Sarma VJ, Hjertberg H, Palmquist B. Monitoring of irrigating fluid absorption during transurethral prostatectomy. A study in anaesthetised patients using a 1% ethanol tagged solution. Anaesthesia 1991: In press.
REPLY My recommendations for prevention of the TURP syndrome were intended only as general guidelines. I am happy that further discussion of this topic has been stimulated. (1) A recent series of 3,885 patients undergoing transurethral prostatectomy was reported by Mebust. He concluded that the TURP syndrome occurred in two percent of patients when the resection time was more than 90 min but in only O.7% when the resection time was less than 90 min. 1A recent review suggested that the resection time be limited to 60 min. 2 The TURP syndrome has occurred as early as after only 15 min of resection time. 3 (2) It has been suggested that the maximum allowable pressure of the irrigating fluid should be 6.9 kPa (70 cm H20), to minimize intravascular absorption. 2 lntravascular absorption occurs when the pressure in the prostatic fossa exceeds the pressure in the pelvic veins, concomitantly with an opening in the pelvic veins. Madsen concluded that absorption was lower when the irrigating fluid was maintained at 5.9 kPa (60 cm 1120) over the table than when the fluid height was maintained at 6.9 kPa (70 cm H20) and 8.8 laPa (90 cm H20. 4 Hahn determined that the intravesicular pressure could vary greatly in different patients even though the irrigating bag was maintained at the same height above the prostatic fossa. 5 He suggested that other factors such as the operating technique of the surgeon and the elastic properties of the bladder were more dominant factors in determining the intravesical pressure than the height of the irrigating bag: Hultdn concluded that the dynamic pressure of the irrigating jet is smaller than the static pressure within the bladder. 6 However, the dynamic pressure is important when the flow rate through the instrument is high and also when flow declines .6 (3) Tagging the irrigating fluid with ethanol and monitoring the expired breath ethanol concentration has been described as a noninvasive technique to detect absorption instantly. 7The rise in expired ethanol occurs immediately after intravascular absorption. 7 Sampling the expired ethanol is an intermittent technique, therefore absorption might be missed if sampling is not performed simultaneously with the absorption. The technique will follow intravascular absorption but does not detect extravascular absorption as readily.S Patients with an elevated serum creatinine concentration have a higher expired ethanol concentration than those with normal renal function, s The irrigating fluM containing 1.5% glycine and 2% ethanol in water has a high osmolality of 650 mosmol, kg -1 and the solution o f l . 5 % glycine and 1% ethanol is still hyperosmolar, s
